About the Web Accessibility design of this Website
(1) Upper block; (2) Center block; (3) Left block; (4) Lower block
Alt+U：Main menu area, this section contains a link to the site's main menu.
Alt+L：Left block, containing the links to the major sections of this site.
Alt+C：Center block, providing the principal information of the page.
Alt+B：The link to the basic functions of this site.